Norwex cloths....blue to clean and purple to dry. They are wonderful and you only use water!
I give mine a good cleaning twice a year (spring and fall) and light cleanings as needed.
Hint clean outside vertically and inside horizontally.... so if there are streaks.... you'll know which side needs help!
First wash with a microfiber cloth and a few drops of ultra Dawn dish liquid in hot water, to cut grease and grime. Rinse well. Follow with distilled white vinegar. Rinse again and squeegee dry, using long strokes and wiping blade between strokes.
Wash windows on an overcast day (or very early AM or after sunset), when no rain is projected and winds are negligible.
Never use cloths that have been laundered in fabric softener. If you use paper towels, Scott brand is recommended. Black and white newsprint was always used by your ancestors for sparkling clean windows.